Systemd-udev-trigger.service not starting at boot up

I have been working on embedded linux system on intel processor. I am facing a strange error , the boot partition not getting mounted using uuid , because the systemd-udev-trigger.service not started at boot which is responsible to trigger udevadm so that /dev/disk/by-uuid directory is created. The status of the service is inactive(dead). How this service is actually started? other related services - systemd-udevd.service , udev kernel socket and udev control socket services are active and running.

# systemctl status systemd-udev-trigger.service
* systemd-udev-trigger.service - Coldplug All udev Devices
     Loaded: loaded ( /lib/systemd/system/systemd-udev-trigger.service8;;; static)
     Active: inactive (dead)
       Docs: 8;;man:udev(7)man:udev(7)8;;
             8;;man:systemd-udevd.service(8)man:systemd-udevd.service(8)8;;

Hi @ManojS,

Loaded: loaded ( /lib/systemd/system/systemd-udev-trigger.service8;;; static)

where does the 8 come from? The Docs section also looks strange.